Fruit and Shoot borer

Conogethes punctiferalis

Conogethes punctiferalis: A Major Polyphagous Pest

Overview

• Conogethes punctiferalis is a widely distributed polyphagous pest found across tropical Asia, including India, Southeast Asia, and Australia.
• It damages over 40 species of fruits, field crops, and forest trees, including peach, apple, mango, papaya, maize, sorghum, sunflower, and castor.
• It is considered a serious pest due to its ability to infest multiple plant parts and predispose them to secondary infections.

Life Stages and Identification

• Eggs:
  • Elliptical, 2-2.5 mm in size.
  • Initially milk-white, later turning light yellow or tangerine.
• Larvae:
  • Mature larvae are 22-26 mm long, with a reddish-brown head and dark red dorsal body.
  • They have eight hair-scales on the mesothorax, metathorax, and abdominal sections.
• Pupae:
  • Brown in color, 13-15 mm long and 4 mm wide.
  • Enclosed in a white silken cocoon with six rolling thorns at the end of the abdomen.
• Adults:
  • Yellow-bodied moths, about 12 mm long.
  • Forewings have 25-30 black spots, hindwings about 15 spots, and additional spots on the abdomen.

Damage and Symptoms

• The larval stage is the most damaging, boring into stems, shoots, buds, fruits, and seeds.
• Affected fruits show boreholes and discoloration, while terminal shoots turn yellow or brown.
• Bored fruits are prone to secondary fungal and bacterial infections.

Distribution and Habitat

• Prefers tropical regions but is also found in subtropical areas such as northern Japan and China.
• Inhabits orchards, agricultural lands, plantations, and natural forests.

Reproductive Biology

• Females lay eggs on or near fruits and seeds.
• Larvae go through five instars before pupating inside larval tunnels.
• Pupation takes 8 days in warm climates but extends up to 8 weeks in cold conditions.

Physiology and Phenology

• Breeds year-round in India and parts of Australia.
• In Japan, two to three generations occur annually.
• In colder regions, larvae overwinter in cocoons and emerge as adults in spring.

Life Cycle Duration

• Completes its cycle in:
  • 28 days on castor oil plants.
  • 31 days on cardamom.
  • 32 days on ginger.

Activity and Host Plant Preference

• Different host plants influence growth, survival, and fecundity.
• Fecundity ranges from 282.3 eggs/female on chestnut trees to just 19.2 eggs/female on apple trees.

Environmental Requirements

• Temperature: Thrives at 24-27°C.
• Humidity: Prefers 60-70% relative humidity.
• Lower temperatures (<8.4°C for eggs, <7.3°C for larvae) negatively affect survival and development.

Management Strategies

• Cultural Control: Timely pruning and removal of infested plant parts.
• Biological Control: Introduction of parasitoids and predators.
• Chemical Control: Use of selective insecticides in severe infestations.
• Integrated Pest Management (IPM): Combination of biological, cultural, and chemical methods for sustainable control.

This polyphagous pest poses a significant threat to agriculture, making effective monitoring and management crucial for minimizing crop losses.